Method and compositions for treating recirculating water systems

ABSTRACT

A novel method and compositions are disclosed for the treatment of water in recirculating water systems. The method includes providing a boron level of at least 20 ppm in the water, continually eroding into the water a compressed sanitizer/algicide component including a halogen source material, a boron source material, and glycoluril, and periodically adding to the water an oxidizing clarifier comprising a chlorine source material, a non-halogen, chlorine source material, and a boron source material. The invention also provides novel water treatment chemicals including the compressed sanitizer/algicide component and the clarifier useful in the foregoing system. The system and compositions are safe and reliable, control algal and fungal growth and generally provide improved water quality for recirculating water systems.

This application is a division of application Ser. No. 08/243,236, filedMay 16, 1994, now U.S. Pat. No. 5,478,482.

FIELD OF THE INVENTION

This invention relates to methods and compositions for the treatment ofrecirculating water systems such as cooling towers, evaporativecondensers, air washers, swimming pools, hot tubs and spas. Theinvention particularly relates to controlling microbial growth,particularly algae and fungi growth.

BACKGROUND OF THE INVENTION

Swimming pools, hot tubs and spas, as well as other water systems, aresubject to contamination from microbes, e.g., algae and fungus, causingunwanted discoloration and turbidity in the water system. Typicalorganisms that will grow in the water in such systems includeChlorococcum, Chloretla, Cledaphora, Microcystis, Oscilratoris,Spirosyra, Olaothrisx, Vanetteria, and Aspergilles flavus. Theprevention or inhibition of growth of these microorganisms in watersystems has been a problem.

It is customary to treat water systems with one or more sanitizersand/or sanitizer/oxidizer combinations to control the growth ofmicroorganisms. The sanitizers most commonly used to control the growthof microorganisms are chemicals that generate hypochlorite orhypobromite species when dissolved in water. There are many hypochloritegenerating chemicals, with the more common ones being chlorine gas,alkali metal hypochlorites such as sodium hypochlorite, alkaline earthmetal hypochlorites such as calcium hypochlorite and lithiumhypochlorite, halogenated hydantoins and chlorinated isocyanuric acidderivatives such as sodium or potassium dichloro-s-triazinetrione.

Although the foregoing halogen species are excellent water treatmentagents, it can be difficult to maintain an efficient level of thehalogens to control the growth of the microorganisms. This is especiallytrue for bromine systems and unstabilized chlorine systems. Thus, it isnecessary with these systems to continuously replace the lost halogens.With this type of treatment program, there frequently are periods ofunnecessarily high halogen levels which are wasteful of the chemicals,and of low to no halogen levels which invite the growth ofmicroorganisms.

Hydrogen peroxide and other inorganic peroxygen compounds, in particularpersulfates and persulfuric acids and their salts, are known to beactive oxygen containing compounds which are also used for oxidation ofwater systems. However, hypochlorite compounds and active oxygencompounds generally are not used together to treat water systems. Infact, the manufacturers of both chlorine compounds and peroxygencompounds, as well as other literature sources, have recommended againstthe blending of these compounds due to their chemical incompatibilitieswhich may lead to explosions or fire.

Also, the Encyclopedia of Chemical Technology (Kirk-Othmer), volume 17,page 1, reports that hydrolysis to H₂ O₂ followed by thedisproportionation of H₂ O₂ is the main path for decomposition ofinorganic peroxide, e.g.,

    K.sub.2 S.sub.2 O.sub.8 +2 H.sub.2 O→2 KHSO.sub.4 +H.sub.2 O.sub.2

Inorganic peroxides neutralize chlorine in water by acting asdechlorinating agents:

    HOCl+H.sub.2 O.sub.2 →O.sub.2 (Ag)+H.sup.+ +Cl.sup.- +H.sub.2 O

Based on the preceding information, it would appear that a combinationof these types of compounds would be impractical.

The separate addition of chlorine compounds and a peroxy compound asoxidizing agents is taught in U.S. Pat. No. 3,702,298 issued November1972 to F. J. Zsoldos et al. This patent teaches the addition of peroxycompounds to swimming pool water containing multivalent metals such asAg and Cu to raise the valence of the metals to a level at which themetals provide an oxidizing action. Chlorine may also be present asdisinfectant in the water system. However, it has not been suggestedthat chlorine source materials be physically combined with the peroxycompounds in the same dry composition.

In U.S. Pat. No. 4,780,216, issued Oct. 25, 1988 to John A. Wojtowicz,there are disclosed calcium hypochlorite sanitizing compositionsconsisting essentially of a mixture of calcium hypochlorite and aperoxydisulfate compound. The compositions are indicated to be useful insanitizing water while helping to minimize the increase in the pH of thewater.

In U.S. Pat. No. 4,594,091, issued Jun. 10, 1986 to John W. Girvan, amethod of controlling algal and fungal growth using sodium tetraborateor potassium tetraborate in water systems is disclosed. The Girvanpatent teaches a method of adding from 10 to 500 ppm boron to watersystems. Girvan teaches the separate addition of the boron material,particularly sodium tetraborate, to a water system, which may alsoinclude a sanitizer. The results achieved with this approach varygreatly from one swimming pool to the next.

The use of calcium hypochlorite mixed with water-soluble, hydratedinorganic salts to provide a composition which is resistant toexothermic, self-propagating decomposition is disclosed in U.S. Pat. No.3,793,216, issued to Dychdala et al. on Feb. 19, 1974. The inorganicsalts are selected from various hydrated alkali metal and alkaline earthmetal phosphates, silicates, borates, carbonates and sulfates.

It has also been known in the prior art to combine boric acid andtrichloro-s-triazinetrione. This combination has been described byindustry practice for the purpose of increasing solubility and reducingoverall raw material costs.

The present invention is surprising in its divergence from teachings ofthe prior art. For example, the prior art has included indications thatboron materials would not be efficacious at the levels utilized herein.See, e.g., Marshall and Hrenoff, Journal of Infectious Diseases, vol.61, p. 42 (1937).

The prior art systems for the treatment of water for controlling growthof antimicrobials have generally had difficulties with providingconsistently dependable results. Theoretical approaches have hadshortcomings in practice because of the need for careful attention towater chemistries. The best of systems are inadequate if they are toodifficult to be used in practice. The present system and compositionsaddress this problem by providing a simple, reliable and consistentsystem for the treatment of water systems.

SUMMARY OF THE INVENTION

Briefly describing one aspect of the present invention, there isprovided a system for the treatment of water systems to controlmicrobial growth. The system includes the addition of boron to the levelof at least about 20 ppm in the water, use of a solid form component tocontinually add both halogen and boron to the water to help maintain thedesired levels of both of these components in the water, and theperiodic addition of a clarification treatment which combines a chlorinecompound, a non-halogen, oxidizing compound and a boron source material.The system provides an effective, reliable approach to the treatment ofwater. In addition, the present invention includes an erodible,boron-containing, compressed sanitizer/algicide component and anoxidizing clarifier.

It is an object of the present invention to provide a method andcompositions for treating water in recirculating water systems toachieve improved water quality more consistently.

A further object of the present invention is to provide for thetreatment of water in swimming pools, hot tubs and spas which allows forquicker swimmer reentry in accordance with current regulatoryguidelines.

It is another object of the present invention to provide chemicalsuseful for water treatment which are safer to transport and use, andwhich have reduced decomposition and packaging deterioration.

Further objects and advantages of the present invention will be apparentfrom the following descriptions and examples.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides a comprehensive system for the treatmentof recirculating water systems utilizing specific compositions whichprovide improved efficacy and reliability for the control of algae andother microorganisms. The compositions include (1) an initial boroncontributor, (2) a solid-form, compressed halogen/boronsanitizer/algicide product, and (3) an oxidizing clarifier comprising achlorine compound, a non-halogen oxidizer, and a boron source. Thissystem has been shown to consistently provide significantly improvedresults over prior approaches. These results have been achieved despiteteachings in the prior art which have suggested away from the presentinvention.

The present invention provides a system and compositions for thetreatment of a variety of recirculating water systems. For example, theinvention is useful for the treatment of cooling towers, evaporativecondensers, air washers, swimming pools, hot tubs and spas. The systemand compositions are readily adapted for use in these and otherenvironments.

No particular mechanisms of action for the compositions and methods ofthe present invention are claimed. However, it has been observed thatthe present invention provides enhanced water quality on a moreconsistent basis. One explanation for this is a synergistic effect ofthe boron materials in the water in combination with, for example,adjunct clarifying materials. A second explanation is the operation ofthe oxidizing clarifier to remove organic impurities, thereby enablingimproved control of microorganisms by the primary, halogen-containingcompressed sanitizer/algicide component.

The present system includes the use of a boron source material forestablishing initial boron levels in the treated water. This iscomplemented by the subsequent, sustained addition of a combination ofhalogen-source material and boron-source material. Finally, a thirdcomposition, added periodically during the period of treatment, enhancesthe operation of the overall system.

The novel method utilizes a boron source composition comprising a sourceof solubilized boron for the water. At the pH of the water systems,e.g., neutral pH in the range 6-8, the boron will be present in thewater primarily in the form of triborate B3O3(OH)4!-1 and tetraborateB4O5(OH)4!-2 polyions. The boron source composition is added initiallyto the water system, for example at the beginning of a pool season, tobring the boron level to at least 20 ppm (by weight). The term boronlevel, as used herein, refers to measurement in terms of elementalboron. The preferred boron level in the treated water ranges from about20 to about 50 ppm, although higher ranges will work. The most preferredrange is 20-26 ppm.

The boron source material may be any suitable compound or mixture. Forexample, this material may be selected from the group consisting ofboric acid, boric oxide (anhydrous boric acid), and compounds having theformula MnBxOy. ZH2O, in which M=any alkali earth or metal/non-metalliccation including but not limited to sodium, potassium, calcium,magnesium and ammonium, n=1 to 3, x=any whole number from 2 to 10,y=3x/2+1, and z=0 to 14. The boron compounds include, for example,disodium tetraborate decahydrate, disodium tetraborate pentahydrate,disodium tetraborate tetrahydrate, disodium octaborate tetrahydrate,sodium pentaborate pentahydrate, sodium metaborate tetrahydrate, sodiummetaborate bihydrate, dipotassium tetraborate tetrahydrate, potassiumpentaborate tetrahydrate, diammonium tetraborate tetrahydrate, andammonium pentaborate tetrahydrate.

It is generally desirable to maintain a neutral pH in the water systemstreated by the present invention. For example, swimming pools arepreferably maintained in the range of pH 7-8. At this pH, the boron willappear as polyborate and tetraborate polyions. The addition of certainspecies of boron, such as tetraborate, will raise the pH of a neutral pHsystem. For example, the addition of sodium tetraborate sufficient toadd 20 ppm of boron to the water, about 1 pound per 1000 gal water, willtypically raise a neutral pH to about 9.0-9.5. If a pH-raising boronsource material is used, it is then required to add a compatible acid,for example sodium bisulfate or muriatic acid, to adjust the pH back tothe desired range.

In the alternative, a pH neutral composition including the boron sourcematerial may be used. In particular, boric acid may be used incombination with another boron source, such as the pH-raising boratespreviously described. A preferred composition is a combination of boricacid and a tetraborate, particularly sodium tetraborate. In thisembodiment, the composition preferably comprises 50-100 parts boric acidand 0-50 parts tetraborate, most preferably 90 parts boric acid and 10parts tetraborate, parts being by weight. Sodium tetraborate (5 mol) isthe preferred compound in this regard.

The second component is a solid form material, hereafter referred to asthe "compressed sanitizer/algicide component", which includes both ahalogen-source composition and a boron-source composition. Thesematerials are blended and formed into a tablet, puck, stick or othersolid form that is conveniently eroded into the system water inconventional fashion, such as by use in a skimmer basket or floater.This compressed sanitizer/algicide component continually adds bothhalogen and boron into the water, which assists in keeping the level ofboth components at the desired ranges.

The halogen-source component may be selected from any compatible halogenmaterial useful in solid form. The halogen is selected from eitherchlorine or bromine, and may comprise any solid-form material whichprovides the halogen in the form of hypohalite ions, i.e. hypochloriteor hypobromite ions, or as hypohalous acid. For example, thehalogen-source component may include various chlorine compoundsincluding calcium hypochlorite, lithium hypochlorite, sodiumdichloro-s-triazinetrione, potassium dischloro-s-triazinetrione andtrichloro-s-triazinetrione. Suitable bromine compounds includebrominated hydantoins and brominated glycoluril.

The boron-source composition is included to provide improvedcharacteristics for the tablet and to assist in maintaining the boronlevel in the water at a desired level. The boron material has been foundto enhance the tablet component in several respects. The tabletsformulated with the boron source material have reduced off-gassing ofchlorine gas. Consequently, the product has less packaging deteriorationand reduced levels of noxious chlorine odor. Also, the boron material ispreferably present in an amount to provide a significant supplement tothe boron in the water.

The boron material may be selected from any of the boron sourcecompositions previously identified. That is, the boron source materialis selected from the group consisting of boric acid, boric oxide, andcompounds having the formula M_(n) B_(x) O_(y).ZH₂ O, in which M, n, x,y and Z are as previously defined.

The respective ranges of the halogen and boron source materials in thissecond component may therefore vary considerably. The suitable rangescan be readily determined by those in the art based on the water systemto be treated, desired erosion rate and/or other physicalcharacteristics of the solid-form component, and other parameters. Inone respect, the halogen is preferably present in an amount sufficientto maintain the desired active halogen level in the water, for example0.5 to 3.0 ppm hypohalite ion in swimming pool water. Also, it has beendetermined that at least certain boron materials will adversely affectthe ability to compound the overall composition into a solid form havingdesirable erosion characteristics. Therefore, there may be a practicallimitation on the amount of boron material which is compounded into thecompressed sanitizer/algicide component. In view of theseconsiderations, the compressed sanitizer/algicide component preferablycomprises 50.0 to 99.9 parts, more preferably 80.0 to 95.0 parts, of thehalogen source material, and 0.1 to 50.0 parts, more preferably 5.0 to20.0 parts, of the boron source material. As used herein, "parts" refersto parts by weight.

It has also been discovered that the addition of glycoluril will provideadvantages both in the compounding of the halogen and boron materialsinto solid form having a controlled, consistent erosion rate, and inenhancing the release and availability of halogen in the water. This isparticularly advantageous since the presence of a boron source materialin the tablet will otherwises result in a substantially increasederosion rate. Combination of the boron and halogen source materialsotherwise provides a solid material which erodes too quickly for use inconventional systems.

The term glycoluril, unless indicated otherwise, is used to generally torefer to compounds including unsubstituted glycoluril, alkyl-substitutedglycoluril, phenyl-substituted glycoluril, chloro-substituted glycoluriland bromo-substituted glycoluril. The compressed sanitizer/algicidecomponent obtains the desired erosion characteristics with asurprisingly low amount of glycoluril. The tablet component may besuitably formulated with not more than 5.0 parts glycoluril. Morepreferably, the tablet component includes 1 to 3 parts glycoluril. Forexample, a particularly preferred composition of the tablet componentconsists of 92.5 parts TCCA, 5 parts sodium tetraborate, and 2.5 partsglycoluril.

The present invention also contemplates the use of an oxidizingclarifier which provides greatly enhanced removal of organic impurities.The clarifier component comprises a unique composition including achlorine source material, a non-halogen, oxygen donor and a boron sourcecompound. This combination is useful in itself as a clarifier, asidefrom the system of the present invention. In addition, when used in theoverall system described herein, the clarifier provides a supplement forthe halogen and boron levels already in the water. When used in theoverall system, the oxidation and clarification properties by theclarifier component enhance the control of microorganisms by thecompressed santizer/algicide component. This third composition alsoconstitutes a surprisingly safe combination of these materials for use.

For the clarifier component, the chlorine source material is ahypochlorite donor selected from lithium hypochlorite, sodium orpotassium dichloro-s-triazinetrione, and trichloro-s-triazinetrione.When used in the foregoing overall system, however, the clarifiercomponent would not include the trichloro-s-triazinetrione.

The non-halogen, oxygen donor is selected from peroxydisulfates andpersulfuric acid salts. The peroxydisulfates may include those havingthe formula: N_(w) S₂ O₈ where N is an alkali metal or alkaline earthmetal or ammonium, and w is 1 or 2. The alkali metal may include sodium,potassium or lithium. The alkaline earth metal may include calcium ormagnesium. The persulfuric acid salts include such compounds as KHSO₄,K₂ SO₄ and 2KHSO₅. An example of a commercial product of persulfuricacid salts is sold by DuPont under the name OXONE™, which consistsessentially of a combination of the compounds KHSO₄, K₂ SO₄ and 2KHSO₅.

The boron source compound is selected from the group previously defined.Particularly preferred compounds are sodium tetraborate and itsderivatives.

For the clarifier component, the constituent materials may be presentover a broad range. Selection of appropriate ranges can be accomplishedby those in the art based on the teachings herein and consideration ofgeneral principles known for the treatment of water. The hypochloritedonor component preferably is present in an amount from 1 to 99 parts,most preferably from 30 to 60 parts, by weight. The non-halogen, oxygendonor component of the composition preferably is present in an amountfrom 1 to 99 parts, more preferably from 5 to 50 parts, by weight. Theboron containing component preferably is present in an amount from 1 to75 parts, more preferably from 5 to 50 parts, by weight. In a preferredembodiment, the clarifier consists essentially of the three components,in which case the foregoing amounts constitute weight percentages in theoverall composition.

The clarifier component may additionally include additives comprisingalgicides, clarifying agents such as aluminum sulfate, dispersants,flocculants and other chemicals typically used for the treatment ofwater systems. By way of example, a preferred composition of theclarifier includes 60% sodium dichloro-s-triazinetrione, 20% sodiumpersulfate, 10% sodium tetraborate, and 10% aluminum sulfate (anadditional clarifying agent).

The clarifier component of the present invention may be produced in anysuitable dry form. For example, the clarifier could be in the form ofgranules, pellets, sticks or tablets. The product is preferablycompounded in a form to provide relatively rapid dispersion, for examplewithin a few hours. This product is added on a periodic basis, forexample weekly, to provide the desired additions of the substituentmaterials, i.e., hypochlorite, oxidant and boron. For example, forapplication to swimming pool water the material is typically added atthe rate of about 1#/10,000 gallons of pool water. This clarifierproduct is designed to oxidize organic and inorganic contaminants and toreplace boron that is lost through loss of pool water.

In addition to enhancing the removal of microorganisms by the compressedsantizer/algicide component, the novel compositions of the presentinvention are safer to transport and use. That is, the combination ofthree components yields a safer composition than for certain of theindividual components, such as the chlorine source material. Forexample, sodium dichloro-s-triazinetrione is classified as an oxidizerper DOT regulations. This classification indicates certain levels ofsafety risks and transportation constraints. By contrast, clarifierproducts formulated based on this disclosed invention have been found tobe non-oxidizers by DOT test, which carry fewer safety risks andtransportation limitations.

The following examples are presented to illustrate more fully thepresent invention:

EXAMPLE 1

The boron level in treated water is raised with various boron containingcompounds. Addition of each of the following compounds in appropriateamounts provides a boron level in excess of 20 ppm in the water: boricacid, boric oxide, disodium tetraborate decahydrate, disodiumtetraborate pentahydrate, disodium tetraborate tetrahydrate, disodiumoctaborate tetrahydrate, sodium pentaborate pentahydrate, sodiummetaborate tetrahydrate, sodium metaborate bihydrate, dipotassiumtetraborate tetrahydrate, potassium pentaborate tetrahydrate, diammoniumtetraborate tetrahydrate, and ammonium pentaborate tetrahydrate.Similarly, addition of appropriate amounts of the foregoing compoundsprovides typically desirable amounts of boron levels in the water, forexample, 20, 26, 30 and 50 ppm. As previously indicated, a preferredcomposition is a combination of boric acid and a pH-raising boroncompound, such as a tetraborate. Combination of these two components inamounts of 50, 90 and 100 parts boric acid, and 50, 10 and 0 partssodium tetraborate, respectively, provide compositions which suitablyadd boron to the water and permit control of the water pH.

EXAMPLE 2

The compressed sanitizer/algicide is prepared from various combinationsof halogen and boron source compounds. The halogen compounds includecalcium hypochlorite, lithium hypochlorite, sodiumdichloro-s-triazinetrione, potassium dichloro-s-triazinetrione andtrichloro-s-triazinetrione, brominated hydantoins and brominatedglycoluril. The boron source compounds include those identified inExample 2. The foregoing compounds are formulated into compressedtablets and the like in conventional fashion. The tablets are preparedwith various amounts of the components, for example 50 and 99.9 partshalogen compound and 0.1 and 50 parts boron composition, respectively,and upon erosion of the tablets, etc. into water provide increasedlevels of halogen and boron in the water. In addition, tablets arecompounded with up to about 5 parts glycoluril of the various typespreviously indicated, and including at levels of 2 and 3 partsglycoluril. Such solid-forms of the sanitizer/algicide compositions arereadily compounded, erode at suitable rates, and provide desirableamounts of halogen and boron to the water.

EXAMPLE 3

The clarifier compositions are formulated by conventional compoundingtechniques from the components previously identified. Included arehypochlorite donors selected from lithium hypochlorite, sodium andpotassium dichloro-s-triazinetrione, and trichloro-s-triazinetrione.Also provided are the non-halogen oxidizers including peroxydisulfatesand persulfuric acid salts previously identified. Finally, the boroncompounds are included from the previous list. Mixing of thesecomponents in amounts of 1, 30, 60 and 99 parts hypochlorite donor, 1,5, 50 and 99 parts non-halogen oxidizer, and 1, 5, 50 and 75 parts boroncontaining compound provides an oxidizer composition which providesimproved clarity to the treated water.

EXAMPLE 4

The Department of Transportation (DOT) manages and regulatestransportation of hazardous materials. The DOT oversees theclassification, description, marking, labeling, packaging, and conditionof hazardous materials transported in the United States. The DOTregulations for the transportation of hazardous materials are currentlyset forth in 49 C.F.R. parts 171-180. Guidelines for the classification,packing group assignment and test methods for oxidizers (Division 5.1materials) are set forth in Appendix F to Part 173, and provide a testmethod to measure the potential for a solid substance to increase theburning rate or burning intensity of a combustible substance when thetwo are thoroughly mixed.

In practice, two tests are run in triplicate for each substance to beevaluated, one at a 1 to 1 ratio, by mass, of the sample to sawdust, andone at a 4 to 1 ratio. For materials classified in Division 5.1, theburning characteristics of each mixture are compared with a standardhaving a 1 to 1 ratio, by mass, of potassium perchlorate and potassiumbromate, as appropriate, to sawdust. For materials classified inDivision 4.1, the packing group is determined using the same method;with ammonium persulfate substituted for the potassium compound.

Potassium perchlorate, potassium bromate and ammonium persulfatetherefore are reference substances. For use in testing, these substancesshould pass through a sieve mesh size smaller than 0.3 mm and should notbe ground. The reference substances are dried at 65 degrees C. for 12hours and kept in a desiccator until required. The combustible materialfor this test is softwood sawdust. It should pass through a sieve meshsampler smaller than 1.6 mm and should contain less than 5% of water byweight.

A 30.0±0.1 g mixture of the reference substance and sawdust in a 1 to 1ratio, by mass, is prepared. For comparison, two 30.0±0.1 g mixtures ofthe material to be tested, in the particle size in which the material isto be transported, and the sawdust, are prepared in ratios of 1 to 1 bymass, and 4 to 1 by mass. Each mixture is mixed mechanically asthoroughly as possible without excessive stress. The test is conductedin a ventilated area under the following ambient conditions: temperature-20 degrees C.±5 degrees C.; humidity--50 percent±10 percent.

Each of the mixtures is formed into a conical pile with dimensions ofapproximately 70 mm base diameter and 60 mm height on a cool,impervious, low-heat conducting surface. The pile is ignited by means ofa wire of inert metal in the form of a circular loop 40 mm in diameterpositioned inside the pile 1 mm above the test surface. The wire isheated electrically to 1000 degrees C. until the first sign ofcombustion is observed, or until it is clear that the pile cannot beignited. The electrical power used to heat the wire is turned off assoon as there is combustion. The time is recorded from the firstobservable sign of combustion to the end of all reaction: smoke, flame,incandescence. The test is repeated three times for each of the twomixing ratios.

A substance is classified in Division 5.1 if, in either concentrationtested, the mean burning time of the sawdust, established from threetests, is equal to or less than that of the average of the three testswith the ammonium persulfate mixture. Packing Group I is assigned to anysubstance which, in either mixture ratio tested, exhibits a burning timeless than potassium bromate. Packing Group II is assigned to anysubstance which, in either mixture ratio tested, exhibits a burning timeequal to or less than that of potassium perchlorate and the criteria forPacking Group I are not met. Packing Group III is assigned to anysubstance which, in either mixture ratio tested, exhibits a burn timeequal to or less than that of ammonium persulfate and the criteria forPacking Groups I and II are not met.

Samples identified in Table 1 were subjected to oxidizer testing inaccordance with the preceding test procedures. When the samples weresubjected to the oxidizer testing, it was anticipated that thecompositions would at least remain in the Division 5.1 oxidizercategory, since that is the classification for sodiumdichloro-s-triazinetrione. However, surprisingly, the tests indicatedthat all three samples were classified as non-oxidizers per DOTstandards. These results are contrary to what would be expected,particularly in view of the fact that manufacturers of chlorineoxidizers and oxygen based oxidizers strongly recommend that thesematerials not be blended together due to incompatibilities.

                  TABLE 1                                                         ______________________________________                                                        SAMPLE #                                                                      150A 147A 150B                                                ______________________________________                                        Sodium dichloro-s-triazinetrione                                                                60%       60%     60%                                       Sodium persulfate 20%       30%     --                                        Sodium tetraborate 5 mol                                                                        10%       10%     10%                                       Aluminum sulfate  10%       --      10%                                       Oxone             --        --      20%                                       ______________________________________                                    

EXAMPLE 5

The three compositions from Example 1 were subjected to additionalhazard testing to determine any incompatibilities. The tests performedwere DTA, Dust Explosion severity, impact sensitivity and self heatingtest. The test results are summarized hereafter, in which DPS refers tosodium persulfate; "dichlor" refers to sodium dichloro-s-triazinetrione,ACL-60 refers to sodium dichloro-s-diazinetrione, borate refers tosodium tetraborate, alum refers to aluminum sulfate, glycoluril refersto unsubstituted glycoluril, and all percentages are by weight.

JANAF THERMAL STABILITY

100% sodium dichloro--slight exotherm at 140 degrees C.; sharp, powerfulexotherm at 147 degrees C.; (rupture disc) catastrophic decomposition,too quick to determine temp/press; would be classified as flammable fortransportation.

IMPACT SENSITIVITY

49.5% sodium dichlor, 49.5% sodium monopersulfate and 1% glycoluril--50%probability of initiation at 18.5 inches.

41% sodium dichlor--50% probability of initiation at 18.5 inches.

DUST EXPLOSION SEVERITY

60% ACL-60, 20% OXONE, 10% borate and 10% alum--no trial produced apositive result.

60% ACL-60, 30% DPS and 10% borate--no trial produced a positive result.

60% ACL-60, 20% DPS, 10% borate and 10% alum--no trial produced apositive result.

IMPACT SENSITIVITY

60% ACL-60, 30% DPS, and 10% borate--each material was subjected to themaximum drop height of 36" with the 2 kgm weight for ten trials permaterial, using a fresh sample each time. No positive result wasobtained in any trial.

60% ACL-60, 20% DPS, and 10% borate--each material was subjected to themaximum drop height of 36" with the 2 kgm weight for ten trials permaterial, using a fresh sample each time. No positive result wasobtained in any trial.

60% ACL-60, 20% OXONE, 10% borate and 10% alum--each material wassubjected to the maximum drop height of 36" with the 2 kgm weight forten trials per material, using a fresh sample each time. No positiveresult was obtained in any trial.

JANAF THERMAL STABILITY (DTA)

60% ACL-60, 20% DPS, 10% borate and 10% alum--in the initial trial withthis material, exothermic behavior was observed at about 111 degrees C.Sample temperature rose over about 90 seconds to about 130 degrees C.,held about 30 seconds, then rose to about 140 degrees C. over about 30seconds, where a sharp, catastrophic reaction caused rupture to the 3000psig disc. A replicate trial produced essentially identical results.

60% ACL-60, 20% OXONE, 10% borate and 10% alum--in the initial trialwith this material, exothermic behavior was observed at about 111degrees C. Sample temperature rose over about 60 seconds to about 124degrees C., paused about 60 seconds, then rose to about 140 degrees C.over about 30 seconds, where a sharp, catastrophic reaction causedidentical results, except that the transition points were less sharplydefined.

JANAF THERMAL STABILITY

60% ACL-60, 30% DPS and 10% borate--in the initial trial with thismaterial, exothermic behavior was observed at about 137 degrees C. About60 seconds later, at about 152 degrees C., a sharp, catastrophicreaction caused rupture of the 3000 psig disc. A replicate trialproduced identical results.

OXIDIZER TESTING

60% ACL-60, 30% DPS and 10% borate--based on the test results, it isrecommended that the material represented by this sample does not needto be classified as an oxidizer, as defined by CFR 49, section 173,Appendix F. Note that while the average burn time of the 4 to 1 ratiowas shorter than the reference, the material was not completelyconsumed.

60% ACL-60, 20% DPS, 10% borate and 10% alum--based on the test results,it is recommended that the material represented by this sample does notneed to be classified as an oxidizer, as defined by CFR 49, section 173,Appendix F. Note that the average burn time of the 1 to 1 ratio mixtureburned considerably longer than the reference. Also, while the averageburn time of the 4 to 1 ratio mixture was shorter than the reference,the material was not completely consumed.

60% ACL-60, 20% OXONE, 10% borate and 10% alum--based on the testresults, it is recommended that the material represented by this sampledoes not need to be classified as an oxidizer, as defined by CFR 49,section 173, Appendix F. Note that the average burn time of the 1 to 1ratio mixture burned considerably longer than the reference. Also, whilethe average burn time of the 4 to 1 ratio mixture was shorter than thereference, the material was not completely consumed.

UN CLASS 4.1 PRELIMINARY SCREEN TEST

60% ACL-60, 20% OXONE, 10% borate and 10% alum--the sample was formedinto an unbroken strip about 250 mm long by 20 mm wide by 10 mm high ona cool, impervious (steel) base plate. Ignition of the sample wasattempted at one end by a gas burner. The sample would not sustainignition after two minutes exposure to the flame. Based on this result,the UN 4.1 Burn Rate Test is not required.

UN CLASS 4.2 PRELIMINARY SCREEN TEST

60% ACL-60, 20% OXONE, 10% borate, and 10% alum--1155.4 grams of thesample were placed into a 10 cc wire mesh basket and covered with alarger wire mesh basket. The sample was maintained at 140 degrees C. for24 hours. Starting at ambient temperature, the sample temperature slowlyclimbed and matched the oven temperature about nine hours after thestart. The temperature continued to rise, reaching a maximum temperatureof 149 degrees C. about 12 hours after start. The temperature then beganto fall, dropping to 146 degrees C., where it remained for the rest ofthe 24 hour test period. After the test, the sample was allowed to cool,then reweighed and examined. The sample experienced an 89.6 gram weightloss and did not exhibit visible change.

Results/Discussion: The impact sensitivity testing for all threecompositions was negative, which indicates that the composition will notexplode on impact. The key indicator for compatibility is the results ofthe DTA testing. The compositions that contained no alum exhibitedexotherms at 137 degrees C., which is approximately the same for 100%ACL-60 (140 degrees C.). The composition which contained alum exhibitedexotherms around 111 degrees C. Although these exotherms for the alumcontaining compositions occurred at a lower temperature, thesecompositions are still considered as safe as calcium hypochlorite whichexotherms at 111 degrees C. The overall results of the combined hazardtesting indicate that these blends will be stable and safe to transport,store and use.

EXAMPLE 6

Several compositions were tested for storage stability at elevatedtemperatures. Two-hundred gram samples of the composition were preparedand sealed in one quart plastic bottles. The bottles were fitted withtwo stopcocks which allow the removal of collected gases. The bottleswere then placed into an oven at 50 degrees C. for 72 hours. At the endof 72 hours, the bottles were removed from the oven and collected gaswas removed from the head space by blowing dry air into the bottle whichforced the collected gas into a gas collecting cylinder which containeda solution of potassium iodide/water/ethanol. The KI solution wastitrated with sodium thiosulfate and the mg of chlorine gas wascalculated. The results are summarized in Table 2.

                  TABLE 2                                                         ______________________________________                                        TEST SUBSTANCE/RESULTS                                                                SODIUM DICHLORO-                                                      BOTTLE #                                                                              S-TRIAZINETRIONE                                                                             OXONE    BORAX  Mg.Cl.sub.2                            ______________________________________                                        A       60%            30%      10%    0.71                                   B       60%            40%      --     1.20                                   C       100%           --       --     1.10                                   ______________________________________                                    

The test results indicate that the compositions are stable and do notproduce excessive chlorine gas during storage at elevated temperatures.

EXAMPLE 7

In this example the oxidation performance of several oxidizer compoundswere evaluated. The oxidation performance was determined by measuringthe destruction of crystal violet dye. The following protocol wasfollowed:

This protocol is designed to evaluate several oxidizer compounds andcombinations of oxidizer compound as potential shock products to be usedin pools and spas.

REAGENTS: Crystal Violet Dye Solution

APPARATUS: pH Meter: equipped with platinum electrode) HACH 3000,Spectrophotometer

PROCEDURE:

1) Prepare the following test solutions:

    ______________________________________                                                        COLUMN A       ppm ACTIVE                                     TEST CMPD.                                                                             gm/L   DILUTION AMOUNT                                                                              AT USE DILUTIONS                               ______________________________________                                        Lithium  2.86    8 ml/l         8 ppm Cl.sub.2                                hypochlorite                                                                  Oxone    1.00   11 ml/l         0.5 ppm O.sub.2                               DPS      1.00   11 ml/l         0.5 ppm O.sub.2                               H.sub.2 O.sub.2                                                                        3.70   30 ml/l        30 ppm                                         ______________________________________                                    

2) Into 1500 ml beakers add 1000 mls of distilled water, 1.64 gm ofphosphate buffer (pH 7.2-7.6) and 15 drops of crystal violet dyesolution. Mix until uniform.

3) Measure initial color number on the HACH 3000 spectrophotometer.Follow HACH method #16. Use distilled water as a blank.

4) Add dilution amount of oxidizer from Column A to the 1 500 ml beaker.Allow to mix 5 mins.

5) Allow beakers to stir for 2 hours. Monitor color number. Calculatepercent color reduction. The results are summarized in Table 3.

                  TABLE 3                                                         ______________________________________                                        TEST       Cl.sub.2 /O.sub.2 Ratio                                                                 Initial   2 Hour                                                                              % Color                                  COMPOUND   (ppm)     Color #   Color #                                                                             Reduction                                ______________________________________                                        LiOCl/Oxone                                                                              8.0/0.5   244        37   85%                                      LiOCl/DPS  8.0/0.5   292        26   91%                                      LiOCl/H.sub.2 O.sub.2                                                                    8.0/30.0  296       268     9.5%                                   LiOCl      8.0/0     288       120   58%                                      DPS        0/0.5     252       252    0                                       Oxone      0/0.5     257       162   37%                                      ______________________________________                                         DPS = Sodium Persulfate                                                       LiOCl = Lithium Hypochlorite                                                  Oxone ™ = Potassium Monopersulfate                                    

The results of this experiment indicate that the oxidation performanceis greatly enhanced when the chlorine oxidizer and the oxygen oxidizerare combined. In fact, the DPS used alone showed no color reduction butin combination with the chlorine achieved a color reduction of 85%.OXONE alone reduced the color only 37%. Chlorine alone showed a colorreduction of 58%. H₂ O₂ another popular oxidizer actually wasantagonistic with chlorine. This experiment points out that the DPS orOxone in the combination with chlorine is not antagonistic, but in factit appears to enhance the oxidation activity.

EXAMPLE 8

During the summer of 1993, a consumer field test was conducted involving48 swimming pools. As a control group, 27 pools were operated by theconsumer only on a traditional chlorine type program utilizing only asanitizer tablet in a chlorinator or floater for 18 weeks. The sanitizertablets contained 92.5% trichloro-s-triazinetrione, 5% sodiumtetraborate (5 mol) and 2.5% unsubstituted glycoluril which added a verylow level of boron, typically less than 0.1 ppm boron for each pound oftablets added to 10,000 gallons of pool water. The consumers providedtheir own shock treatment and shocked the water at their discretion. Thepools were monitored for algae growth during the test period. During the18 weeks, 81.5% of the pools experienced algae growth. The results aresummarized in Table 4.

                                      TABLE 4                                     __________________________________________________________________________      WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK                       No                                                                              1  2  3  4  5  6  7  8  9  10 11 12 13 14 15 16 17 18                       __________________________________________________________________________    1                XX XX             XX             XX                          3                                                                             4 XX                         XX          XX                                   5             XX                                                              6 XX XX                XX          XX       XX XX                             7                   XX XX                            XX                       8 XX          XX       XX                                                     9 XX XX                                        XX                             10   XX    XX XX    XX XX       XX       XX XX                                11                                                                              XX    XX                      XX XX       XX XX                             12                                                                            13                                                                              XX XX                   XX             XX    XX                             14                                                                            15                  XX                                                        16            XX                                                              17                  XX                                                        18            XX XX XX                                                        19                                             XX XX XX                       20         XX    XX XX    XX                                                  21                                                                              XX XX XX XX XX XX XX XX    XX                                               22                                                                            23                     XX                                                     24               XX    XX XX XX XX       XX XX XX XX XX                       25                              XX XX    XX XX                                26      XX XX XX       XX XX XX XX XX                                         27                                                                              XX XX XX XX    XX XX XX XX XX XX XX XX XX                                   __________________________________________________________________________     The XX denotes algae growth.                                             

At the beginning of week 19, pool numbers 1-13 were given a lithiumhypochlorite treatment on a weekly basis at the rate of 1 pound for upto 30,000 gallons of swimming pool water. Also at the beginning of week19, pools 14-27 were given the clarifier product that contained 60%sodium dichloro-s-triazinetrione, 20% potassium monopersulfate, 10%sodium tetraborate (5 mol) and 10% aluminum sulfate on a weekly basis atthe rate of 1# for up to 30,000 gallons of swimming pool water. Thetesting was continued until week number 36. The number of reported algaeincidences were reduced, but still constituted 52% of the pools.dencesto 52% of the pools. The results are summarized in Table 5.

                                      TABLE 5                                     __________________________________________________________________________      WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK                       No                                                                              19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36                       __________________________________________________________________________    2                                                                             3                                                                             4             XX    XX                                                        5                                                                             6                                                                             7                                  XX                                         8                                  XX                                         9                                                                             10                                                                              XX                                                                          11      XX             XX                                                     12                                                                            13                                                                            14                                                                            15                                                                            16                                                                              XX                                                                          17                                                                            18         XX                                                                 19                     XX    XX                                               20            XX       XX                                                     21                                                                            22      XX                                                                    23      XX                                                                    24      XX XX XX XX                                                           25                                                                            26                              XX XX                                         27                                                                              XX                                                                          __________________________________________________________________________     The XX denotes algae growth.                                             

By comparison, 16 pools were initially operated on a commerciallyavailable boron system with boron levels maintained at less than 20 ppm.The same chlorine sanitizer tablet used in the previous pools was alsoused to treat these pools. The chlorine tablets were added to the poolthrough a chlorinator or a floater. The consumers added their own shocktreatment at their discretion. During the 18 week test period, 62% ofthese pools experienced algae growth. The test results are summarized inTable 6.

                                      TABLE 6                                     __________________________________________________________________________       WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK                      No 1  2  3  4  5  6  7  8  9  10 11 12 13 14 15 16 17 18                      __________________________________________________________________________    TM 79 81 81 82 84 85 86 86 87 86 87 87 87 87 87 86 86 85                      25 XX                                                                         26 XX XX XX XX XX XX                                                          27                                                                            28                                     XX                                     29 XX XX XX XX XX XX XX XX XX                XX XX                            30    XX XX                   XX                                              31                                                                            32                                                                            33                                                                            34                            XX                                              35                                                                            36                                              XX                            37 XX                                                                         38 XX       XX    XX                      XX    XX XX                         39                                                                            40             XX                               XX XX XX                      __________________________________________________________________________     The XX denotes algae growth.                                             

At the beginning of weeks 17-19, these 16 pools were converted to themethod of the present invention. The boron levels were increased to26-30 ppm. Sanitizer tablets containing 92.5%trichloro-s-triazinetrione, 5% sodium tetraborate 5 mol and 2.5%unsubstituted glycoluril were used to provide both chlorine and boron ona continuous basis. The pools were treated with blended clarifiercomponent on a weekly basis at the rate of 1 pound for up to 30,000gallons of pool water. During the 19 weeks, only three pools (19.0%)reported algae growth. One pool reported algae growth during week #23due to mechanical problems resulting in an interruption of the chlorinefeed system and subsequent chlorine readings of 0 ppm. The test resultsare summarized in Table 7.

                                      TABLE 7                                     __________________________________________________________________________       WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK WK                      No 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36                      __________________________________________________________________________    TM 79 81 81 82 84 85 86 86 87 86 87 87 87 87 87 86 86 85                      25                                                                            26                                                                            27                                                                            28                                                                            29                                                                            30                                                                            31 XX                                                                         32             XX                                                             33                                                                            34                                                                            35                                                                            36                                                                            37                                                                            38                                                                            39                                                                            40 XX                                                                         __________________________________________________________________________     The XX denotes algae growth.                                             

The results of the 36 week field test clearly indicate that the methodof the present invention reduces the growth of algae.

EXAMPLE 9

The treatment of various recirculating systems is repeated in accordancewith the present invention and the process of Example 8 using thevarious products referenced in Examples 1-3 and suitable results alongthe lines of Example 8 are achieved.

EXAMPLE 10

The loss of the boron component in a water system was demonstrated in a22,000 gallon swimming pool located in North Atlanta, Georgia. Sodiumtetraborate was added to the pool to achieve a concentration of 26 ppmof boron in the pool. The pool continued to operate on a chlorinesanitizer with weekly shock treatments. Seven months later, the poolwater was rechecked. The boron level had dropped to 20 ppm, pointing outthat the boron is depleted with time and must be continuallyreplenished.

What is claimed is:
 1. A clarifier composition for use in theclarification of recirculating water which comprises a combination of achlorine source material for providing hypochlorite ions to the water, anon-halogen, oxygen donor material, and a boron source material, thechlorine source material being selected from the group consisting oflithium hypochlorite, sodium or potassium dichloro-s-triazinetrione andtrichloro-s-triazinetrione.
 2. The composition of claim 1 in which thenon-halogen, oxygen donor material is selected from the group consistingof peroxydisulfates and persulfuric acid salts.
 3. The composition ofclaim 1 in which the boron source material is selected from the groupconsisting of boric acid, boric oxide, and compounds having the formulaM_(n) B_(x) O_(y).ZH₂ O, in which M=sodium, potassium, calcium,magnesium or ammonium, n=1 to 3, x=any whole number from 2 to 10,y=3x/2+1, and z=0 to
 14. 4. The composition of claim 1 which comprises 1to 99 parts chlorine source material, 1 to 99 parts non-halogen, oxygendonor material, and 1 to 75 parts boron source material.
 5. Thecomposition of claim 4 which comprises 30 to 60 parts chlorine sourcematerial, 5 to 50 parts non-halogen, oxygen donor material, and 5 to 50parts boron source material.
 6. A clarifier composition for use in theclarification of recirculating water which consists essentially ofchlorine source material for providing hypochlorite ions to the water, anon-halogen, oxygen donor material, and a boron source material.
 7. Amethod for clarifying recirculating water which comprises adding to thewater a clarifier composition comprising a combination of a chlorinesource material for providing hypochlorite ions to the water, anon-halogen, oxygen donor material, and a boron source material, saidchlorine source material being selected from the group consisting oflithium hypochlorite, sodium or potassium dichloro-s-triazinetrione andtrichloro-s-triazinetrione.
 8. The method of claim 7 which comprisesadding to the water an amount of the clarifier composition to providefrom about 1 to about 3 ppm hypochlorite ion in the water.
 9. A methodfor clarifying recirculating water which comprises adding to the water aclarifier composition comprising a combination of a chlorine sourcematerial for providing hypochlorite ions to the water, a non-halogen,oxygen donor material, and a boron source material, the clarifiercomposition comprising a chlorine source material selected from thegroup consisting of lithium hypochlorite, sodium or potassiumdichloro-s-triazinetrione and trichloro-s-triazinetrione, thenon-halogen, oxygen source material being selected from the groupconsisting of peroxydisulfates and persulfuric acid salts, and the boronsource material being selected from the group consisting of boric acid,boric oxide, and compounds having the formula M_(n) B_(x) O_(y).ZH₂ O,in which M=sodium, potassium, calcium, magnesium or ammonium, n=1 to 3,x=any whole number from 2 to 10, y=3x/2+1, and z=0 to
 14. 10. The methodof claim 9 in which the clarifier composition comprises 1 to 99 partschlorine source material, 1 to 99 parts non-halogen, oxygen donormaterial, and 1 to 75 parts boron source material.
 11. The method ofclaim 10 in which the clarifier composition comprises 30 to 60 partschlorine source material, 5 to 50 parts non-halogen, oxygen donormaterial, and 5 to 50 parts boron source material.
 12. The method ofclaim 11 in which the clarifier composition consists essentially ofchlorine source material, non-halogen, oxygen donor material, and boronsource material.
 13. The clarifier composition of claim 1 which is inthe form of granules, pellets, sticks or tablets.
 14. The composition ofclaim 1 in which the non-halogen, oxygen source material is selectedfrom the group consisting of peroxydisulfates and persulfuric acidsalts.
 15. The composition of claim 1 in which the boron source materialis selected from the group consisting of boric acid, boric oxide, andcompounds having the formula M_(n) B_(x) O_(y).ZH₂, in which M=sodium,potassium, calcium, magnesium or ammonium, n=1 to 3, x=any whole numberfrom 2 to 10, y=3x/2+1, and z=0 to
 14. 16. The composition of claim 1which comprises 1 to 99 parts chlorine source material, 1 to 99 partsnon-halogen, oxygen donor material, and 1 to 75 parts boron sourcematerial.
 17. The composition of claim 16 which comprises 30 to 60 partschlorine source material, 5 to 50 parts non-halogen, oxygen donormaterial, and 5 to 50 parts boron source material.
 18. The compositionof claim 6 which comprises 1 to 99 parts chlorine source material, 1 to99 parts non-halogen, oxygen donor material, and 1 to 75 parts boronsource material.
 19. The composition of claim 18 which comprises 30 to60 parts chlorine source material, 5 to 50 parts non-halogen, oxygendonor material, and 5 to 50 parts boron source material.
 20. The methodof claim 7 in which the clarifier composition is in the form ofgranules, pellets, sticks or tablets.
 21. The method of claim 7 in whichthe clarifier composition comprises 1 to 99 parts chlorine sourcematerial, 1 to 99 parts non-halogen, oxygen donor material, and 1 to 75parts boron source material.
 22. The method of claim 21 in which theclarifier composition comprises 30 to 60 parts chlorine source material,5 to 50 parts non-halogen, oxygen donor material, and 5 to 50 partsboron source material.
 23. The method of claim 22 in which the clarifiercomposition consists essentially of chlorine source material,non-halogen, oxygen donor material, and boron source material.